It's a woman on a pedestal, like the expression: "women should be placed upon a pedestal." The phrase is usually understood to mean that men should treat women with respect, treating them as if they are more important than themselves.
I also thought pedastal. I guess it has been a long time
since I've seen a woman wear a skirt. But I think your interpretation of why is off. I was looking for something sexist (as per OP) so the pedestal fit that for me. I presumed it was an inside joke amoung guys. But since someone pointed out the skirt I know know I was reading into it incorrectly
I didn't down vote you, and I have no special insight into why others have, but my guess would be that at least some of those votes were meant to indicate disagreement with your interpretation: I think more people see the equal sign as representing legs, rather than a pedestal.
If I were to speculate further, I would suspect that some people are wary of interpretations of ambiguous texts that unnecessarily imply sexist/culturally fraught meanings.
Well first, that's not an expression that anyone uses. If there is one, it's the opposite of that. Also, your interpretation of that is incorrect.
Putting something on a pedestal is bad. It's pretending that it's perfect. If you put a person on a pedestal, you remove their humanity and flaws and aren't treating them like a person.